Mid-March Update

I think the basic running in is about done. The Tdi has done about 550 miles and is starting well, not loosing any fluids and not smoking. The thin trace of blue smoke when accelerating has gone and there’s the faintest trace of black smoke in its place, suggesting the new bores and rings are bedding in nicely.

The idle RPM dropped significantly after the first hundred or so miles, as did the oil pressure, but I’m now satisfied that this was due to the engine bedding in and the compression ratio increasing as the rings create a better seal. It makes the engine slightly harsher, but obvioulsy its economy and perfomance will be improved.

I was going to replace the oil with normal semi-synthetic today, along with the oil and fuel filters, adjust the injection pump’s idle setting and check the tappet clearances, but given the weather, the sofa is a better bet!

After having a go at resetting the gear box selectors, things improved markedly for a while, but yesterday’s drive to and from resulted in 4th jumping out again on the over-run several times. I’m still at a loss to understand why – the 3rd/4th synchro unit was replaced when I rebuilt the gear box just over 6,000 miles ago and still looks mint, and since 4th just locks the input and main shafts together, there is no helical gear to knock the synchro hub aft as a torsional shunt occurs. The main shaft’s end float is slightly greater than the specified amount, but it’s not huge (about 0.5mm). The selector shaft appears to be in good condition, and the shaft’s detent ball and spring seem fine. Time to speak to a few experts, I think.

Other than that, it’s running very well. The 109 accelerates swiftly and cruises very comfortably at 60mph, but I can maintain 70mph up fairly steep hills and 80+ on the flat if needed. I suspect without the roof rack that it’d easily add another 10mph to both those top speeds. The noise level has decreased inside, too.

Now that the running in is fundamentally done, I’ll be starting to collect data on fill-up quantities and mileages to work out its average fuel consumption, but so far it seems to be noticeably better than the 12J, and I’d guess at the high twenties, perhaps 30mpg.

I have also tried out the Kenlowe Hotstart a few times, and given about 40 minutes, it’ll get the engine up to full operating temeprature. That means it’ll be staying put under the bonnet. One mod that needs doing now, though, is to fit a solenoid valve to the coolant lines of the fuel heat exchanger so that the fuel is left cold when running on diesel but heated when on SVO. I just need to find a cheap source of SVO now that the supermarkets have stopped selling it in large containers and also nearly doubled their prices.